Google Authenticator is merely a generic TOTP token storage app. The person you're replying to was pointing out that Google Authenticator, specifically, isn't necessary. There are alternatives, and unless you're using a company-owned device that restricts the apps you can use there is no way for work to dictate which app you use for TOTP tokens.

Duo, Okta Verify, and other 2FA apps that use push notifications and such, are a different beast altogether.

they are interchangeable. you can export from google to use in proton. I’ve set all my google logins to proton too. I’ve not experienced this ‘locked in’ situation if you’re using your own phone to run the app.

My work has me using 3 different 2FA apps depending on what service I'm accessing. It's great! Especially with the noticable battery consumption increase after setting up 2 more 2FA apps than I had before